MOSCOW, Idaho -

A University of Idaho professor was among a group of scientists who witnessed a rare melting event of the ice sheet covering Greenland last summer - and then figured out what likely caused it.
    
Von Walden says that's what convinced scientific journal Nature to publish their article, putting it on the cover this month.
    
In an interview with the Moscow-Pullman Daily News, Walden says he was at the Summit field research station on Greenland last July.
    
That's when his group documented the first rapid melt of the ice sheet since 1889, he said.
    
He helped determine that just the right amount of thickness and type of cloud led to the rare event.
    
Walden says he did some shouting and dancing when he saw his article on the Nature cover.